Tanning



FATENT @FMQEQ Anon MMER, or'srurreaar, AND LOUIS BLANGEY, or mannnem, GERMANY;

assIeNoRs, BY mnsna assrcnmams; To me cnmaioan FOUNDATION, Inc, a

CORPORATION OF DELAWARE.

Specification of Letters Patent.

rename.

Patented July 4,1922.

No Drawing. original application filed September 2, 1916, Serial No. 118,286, Divided and this app.

T all whom it may concern:

Be it known that we, AnoLF Roman and Lows BLANGEY, citizens of the German Empire and of the Swim Republic, respectively, residing at Stuttgart andMannheim,

respectively, Germany, have invented new and useful Improvements in Tanning, of which the following is a specification.

The present invention relates to certain improvements in tanning with artificially produced tanning materials and is divided out from our'co-pending application Serial Number 118,286, filed September 2, 1916, for the same invention.

' As is known, the'vegetable tannin materials employed for tanning hides without exception possess an amorphous character. In our original application Serial 7 No. 118,286, filed September 2, 1916, we have described that we can transform-hides into a valuable leather by means of organic bodies which contain sulfonic or carboxylic acid groups or both these groups, having a crystalline character and being soluble in water and capable of precipitating glue or gelatine from solutions thereof.- The object of the present invention is to make specific claims for tanning with a grou of compounds of the aforesaid character w lch is characterized by being prepared without the action of formaldehyde and therefore,

containing no CH -groups connecting two or more aromatic nuclei.

The bodies can be used for tanning either alone or together with natural or synthetic tanning materials of other kind or mixed 1 parts are by weight.

E wample 1..

Dissolve 228 parts of 4 .4'-dih droxydiphenyl dimethylmethane (see nnalen der Chemie, vol. 343, p. 85) in 1200 parts of dry nitrobenzene and add, whilst stir I filtered and cation filed April 37, 1817. Semi No. 165,000.

ring, 234 parts of chloro-sulfonic acid, at a temperature of 05 G. Allow to stand for several hours, blow out the hydrogen chlorld dissolved by a current of air, then pour the mass into water, separate the mtrobenzene and neutralize the aqueous solution wlth barium carbonate. The solutlon of the barium salt is filtered off and evaporated until crystallization begins. The barium salt whlch separates out is washed formed into the free sulfonic acid by treating with exactly the required quantity of dlluted sulfuric acid. The liquid is then evaporated in vacuo at about 80 (7.; the free sulfonic acid is hereby 0btalned in the form of a syrupy mass which solidifies to a crystalline mass when having been allowed to stand. for. some time,

The watery solution of this acid can be used for tanning in the usual manner. I

In quite an analogous manner a sulfonic acid of 4. 1 dihydroxy 3.3 dimethyl diphenyl-dimethyl-methane (Annalen der Cliemie, vol. 400, p. 33) can be obtained.

Emample $2.

A tanning bath is prepared by dissolving n water-together, if desired, with suitable other components a sulfonic acid as can be prepared by treating the condensation product of meta-cresol, para-cresol or alphanaphthol and acetone (Annalen der Chemie, vol. 388. p. 304; Berichte der Deutschen Chemischen Gesellschaft, 'vol. 2-5, Refer-ate p. 336) with fuming sulfuric acid or chlorosulfonic acid.

Example 3.

Hides can be tanned by using a sulfonic acid prepared as follows.

128 parts of 4-.d-dihydroxy-3.3'-dimethyldiphenyl-dimethyl-methane possessing the formula dit 5Q are treated for several hours on the waterbath with 252 parts of crystallized sodium sulfite dissolved in 1000 parts of water and 100 parts of 30% formaldehyde until a test when acidified gives no longer a precipi,

with a little cold water and trans-l tate. The solution is then acidifiedby adding hydrochloric acid whereupon 125 parts of crystallized barium chlorid are dissolved therein. When cold, the barium salt which has separated out, is filtered ofi', re-

crystallized if necessary and converted, in

the usual way, into the free sulfonic acid or its Sodium salt, the latter representing an easily crystallizing compound. sulfonic acid can serve for tanning directly, the sodium fected in the usual manner.

Ewample 4. Treat hides in the usual way with an aqueous solution of 5.5-dihydroxy-2.2-dinaphthylamine-7 .7 -disulfonic acid (obtainable according to Example 2 of German Letters Patent No. 114,974).

Ewample 5.

50 parts of 4.4-dihydroxy-benzophenone (Annalen der Chemie, vol. 218, p. 354) are dissolved in 200 parts of monohydratic sulfuric acid, then 150 parts of fuming sulfuric acid containing 23% S0 are added and the mixture is stirred at ordinary temperature, until a, test is clearly soluble in water. The sulfonic acid can be obtained in a pure free state by decom osing its barium salt by the required quantity of sulfuric acid; the aqueous solution thereof can be used directly for tanning.

! Example 6.

Treat hides in the usual way with an aqueous solution of anthraquinone-beta-sul- 'fonic or 2.6-disulfonic acid or 1.4-dichloro-' anthraquinone sulfonic acid, or hydroxyornitro-anthraquinone sulfonic acids or naphthanthraquinone sulfonic acids or with the respective salts in the presence of acid.

While compounds such as the afore-de scribed, possessing the above stated characteristic properties and containing in their molecule more than one aromatic nucleus connected by one or more polyvalent atoms,

are particularly suitable for the claimed process, other compounds containing sulfonic or carboxylic acid groups and capable of precipitating glue, or gelatine, solutions are also suitable for the purpose of the present invention. Instances of such compounds are naphtholor naphthylamine sulfonic acids capable of precipitating glue, such as lA-naphthol sulfonic acid, 2.6-naphthol-sul- I fonic acid, 1.2.4? or 2.1.5- naphthylaminedisulfonic acids, etc. i

It is, of course, to be understood that the claims are intended to cover the solutions of the respective salts of the acids specified in the claims, preferably in acid solution, as well as such acids themselves.

The free.

salt after being acidified.

With the watery solution of this substance, the tanning process can otherwise be efglue from solutions t The following procedure sets forth an illustrative embodiment of a manner in which my invention may be carried lnto practice:

I 100 parts of a sulphonic acid prepared as set forth in the above examples may be dissolved in about. 1600 parts of water. Hides which have been limed and bated are introduced into a vat containing the tanning solution prepared as above and allowed to re-' main therein for a period of from 8 to 12 days. The leather thus obtained is subsequently dried and may be treated with'fat -.in the usual manner.

aromatic compound, of crystalline structure consistlng of more than one aromatic nucleus connected to at least one carbon atom whlch is itself joined to at least one alkyl cipitating glue from solutions thereof, substantially ofthe character described.

3. The process of tanning which comprises treating hideswith a water soluble aromatic compound of crystalline structure consisting of at least two aromatic nuclei connected to at least one carbon atom which is itself joined'to at least one alkyl group group and containing a sulphonic acid group, said compound being capable of preandcontaining a mineral acid group, said compound being capable of precipitating ereof, substantially of the character described.

4. The process of tanning prises treating hides with a water-soluble aromatic compound of crystalline structure consisting of at least two aromatic nuclei connected to at least one carbon atom which is itself joined to at least one alkyl group and containing a sulphonic acid group, said glue from solutions thereof, substantially of the character described' I o. The process of tanning which comprlses treating hides with a watery solution of a crystalline sulfonic acid derived from anthraquinone, substantially of the character described;

In testimony whereof we have hereunto set our hands. I

ADOLF RoMER. LOUIS BLANGEY.

which comcompound belng capable of precipltating 

